Find All Elements By Tag Name Name Space : DOM Element « XML « Java Tutorial

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.LinkedList;
import java.util.List;

import javax.xml.namespace.QName;

import org.w3c.dom.Element;
import org.w3c.dom.Node;

/**
 * Few simple utils to read DOM. This is originally from the Jakarta Commons
 * Modeler.
 * 
 * @author Costin Manolache
 */
public class Utils {
  public static List<Element> findAllElementsByTagNameNS(Element elem, String nameSpaceURI,
      String localName) {
    List<Element> ret = new LinkedList<Element>();
    findAllElementsByTagNameNS(elem, nameSpaceURI, localName, ret);
    return ret;
  }

  private static void findAllElementsByTagName(Element el, String tagName, List<Element> elementList) {

    if (tagName.equals(el.getTagName())) {
      elementList.add(el);
    }
    Element elem = getFirstElement(el);
    while (elem != null) {
      findAllElementsByTagName(elem, tagName, elementList);
      elem = getNextElement(elem);
    }
  }

  private static void findAllElementsByTagNameNS(Element el, String nameSpaceURI, String localName,
      List<Element> elementList) {

    if (localName.equals(el.getLocalName()) && nameSpaceURI.contains(el.getNamespaceURI())) {
      elementList.add(el);
    }
    Element elem = getFirstElement(el);
    while (elem != null) {
      findAllElementsByTagNameNS(elem, nameSpaceURI, localName, elementList);
      elem = getNextElement(elem);
    }
  }

  public static Element getFirstElement(Node parent) {
    Node n = parent.getFirstChild();
    while (n != null && Node.ELEMENT_NODE != n.getNodeType()) {
      n = n.getNextSibling();
    }
    if (n == null) {
      return null;
    }
    return (Element) n;
  }

  public static Element getNextElement(Element el) {
    Node nd = el.getNextSibling();
    while (nd != null) {
      if (nd.getNodeType() == Node.ELEMENT_NODE) {
        return (Element) nd;
      }
      nd = nd.getNextSibling();
    }
    return null;
  }

}